An inkjet recording system is a printing system in which printing is conducted by spraying a liquid ink with a high degree of fluidity from very fine nozzles, and adhering that ink to a recording medium such as a sheet of paper. These systems enable the printing of high-resolution, high-quality images at high speed and with minimal noise, using a comparatively inexpensive printing apparatus, and are rapidly becoming widespread.
The coloring materials for the inks used in these inkjet recording systems can be broadly classified into materials that use pigments and materials that use dyes. Of these, there is a growing tendency for the use of inks that use pigments as the coloring materials, as such inks exhibit the excellent levels of light resistance, weather resistance and water resistance that are required for high image quality printing.
In terms of the solvent, inks can be broadly classified into aqueous inks and non-aqueous inks. Non-aqueous inks that do not use water as the ink solvent, including solvent-based inks that use a volatile solvent as the main constituent and oil-based inks that use a non-volatile solvent as the main constituent, exhibit superior stability within the printer (such as intermittent dischargeability and discharge recovery following standing idle for a long period), cause no curling of the printed paper and have a short ink penetration and drying time, and are therefore attracting considerable attention.    [Patent Document 1] Japanese Patent Laid-Open No. 2003-261808    [Patent Document 2] Japanese Patent Laid-Open No. 2007-126564